The aim of this paper is to develop the L p John ellipsoid for the geometry of log-concave functions. Using the results of the L p Minkowski theory for log-concave function established in [26], we characterize the L p John ellipsoid for log-concave function, and establish some inequalities of the L p John ellipsoid for log-concave function. Finally, the analog of Ball's volume ratio inequality for the L p John ellipsoid of log-concave function is established.